Identification of genes involved in the formation of soluble dietary fiber in winter rye grain and their expression in cultivars with different viscosities of wholemeal water extract

The grain of rye(Secale cereale L.) used for baking contains a large amount of non-starch polysaccharides,making it an excellent component of functional foods. But rye grain intended for alcohol production and forage use should have a reduced content of these polysaccharides. A comprehensive parameter that can predict the best field of application for winter rye grain is the viscosity of its wholemeal water extract.However, our understanding of the genetic background underlying this key trait and associated features of rye grain is poor. By analyzing six Russian winter rye cultivars, we identified the most contrasting forms and characterized the peculiarities of their water-soluble carbohydrates capable of influencing the viscosity of water extracts. Then, using phylogenetic and transcriptomic analyses, we identified in the rye genome many genes encoding putative glycosyltransferases and glycosylhydrolases responsible for the synthesis and degradation of arabinoxylans, mixed-linkage glucans, cellulose, and some other polysaccharides. We determined the dynamics of m RNA abundance for these genes at three stages of kernel development. Comparisons of gene expression levels in two contrasting cultivars revealed specific members of multigene families that may serve as promising targets for manipulating non-starch polysaccharide content in rye grain. High-viscosity cultivars were characterized by up-regulation of many glycosyltransferases involved in the biosynthesis of arabinoxylans and other cell-wall polysaccharides,whereas low-viscosity cultivars showed up-regulation of several genes encoding polysaccharidedegrading enzymes.

Photorespiration and Its Role in the Regulation of Photosynthesis and Plant Productivity

The results of long-term studies of photorespiration are summarized and the unsuccessful attempts to increase productivity by suppressing this process are shown. It has been shown that photorespiration and glycolate metabolism are involved in the regulation of the relationship between light processes in chloroplasts and the dark reactions of carbon dioxide assimilation. The studies were conducted on plants in vivo and were associated with the activity of the apoplastic invertase enzyme, affecting assimilate transport. In violation of donor-acceptor relations between photosynthetic and plant-assimilating organs (removal of part of organs-consumers of assimilates or leaves, increase in nitrate nutrition), the kinetics of inclusion of 14C in glycolate was changed. This is due to the strengthening of the role of the transketolase mechanism of its formation. The study of genetically transformed plants, in which either an additional apoplastic invertase gene was introduced, or the existing gene was blocked and did not act, showed a different change in the ratio of 14C-labeled sucrose/hexose and the transpiration response to reduced light. In this connection, the concept of the mechanism of photorespiration interaction with apoplastic invertase and stomatal apparatus of the leaf is proposed when the ratio of light and dark reactions of photosynthesis or assimilate transport is changed. The essence of the concept is that when the ratio of light and dark processes is disturbed, the concentration of organic acids changes first in mesophilic cells (mainly by photorespiration), and then in the extracellular space. It changes the activity of apoplastic invertase, which hydrolyzes sucrose and prevents it from being exported from the leaf. Hydrolysis of sucrose increases the osmoticity of the aquatic environment of the apoplast, which increases with movement to the stomata. The changed osmoticity of the environment around the stomatal guard cells changes the resistance of CO2 diffusion into the leaf. This normalizes the ratio of light and dark processes in the sheet. Therefore, when illumination decreases, nitrate nutrition increases or difficulties arise with the use of photosynthesis products in acceptor organs, the ratio of 14C-labeled sucrose/hexose decreases, and the stomata close. With increasing illumination, reverse events occur.

Ecological Significance of the Interaction of Photosynthesis Light and Dark Processes

The kinetics of 14C incorporation into glycolate was studied after changing the export of photosynthetic products from the leaf. It has been shown that the ribulose-bisphosphate-oxygenase pathway of glycolate formation works in the stationary state of the plant. An excess of photosyntates or a decrease in the amount of light primary products, as well as nitrates in the leaves, immediately turns on the transketolase pathway of glycolate formation. In this case, part of the oxygen formed in the photochemical reactions of chloroplasts ceases to be released from the leaf. After oxygen receives an electron from ferredoxin in the electron transport chain of chloroplasts, it starts (through photorespiration) the formation of non-carbohydrate photosyntates and metabolic processes in the cytoplasm. It was concluded that the main function of photorespiration in the regulation of photosynthesis is maintaining a balance between light and dark processes of photosynthesis on change of living conditions.

Application of prodigiosin as a colorant for polyolefines

Serratia marcescens strain 9986 is a producer of prodigiosin used as a dye of polyolefines (polyethylene, ultratene). The biosynthesis of pigment was closely connected with controlled growth parameters. A prodigiosin yield 0.2 - 0.4 mg per l of culture medium in the batch culture under aerobic conditions was obtained. Prodigiosin was extracted from crude biomass treated by 0.1% of sodium dodecyl sulfate (SDS). This novel elaborated stage is necessary for thermostability a dye in polymer. The consumption of prodigiosin preparation is more economical in the technology of the coloration of polyolefines. The elaborated method has been manufactured for dyeing polyethylene by biological pigment-articles of the common use corresponding to the technological standard.

Synaptic mechanisms of cadmium neurotoxicity

Cadmium(Cd) is a toxic heavy metal ubiquitously distributed in the environment(water, air, food, smoke) with extreme ability to accumulate in the human body due to its delayed clearance(half-life time 15–30 years).

Silica-based nanoarchitecture for an optimal combination of photothermal and chemodynamic therapy functions of Cu2–xS cores with red emitting carbon dots

This study introduces multifunctional silica nanoparticles that exhibit both high photothermal and chemodynamic therapeutic activities,in addition to luminescence.The activity of the silica nanoparticles is derived from their plasmonic properties,which are a result of infusing the silica nanoparticles with multiple Cu2-xS cores.This infusion process is facilitated by a recoating of the silica nanoparticles with a cationic surfactant.The key factors that enable the internal incorporation of the Cu2-xS cores and the external deposition of red-emitting carbon dots are identified.The Cu2-xS cores within the silica nanoparticles exhibit both self-boosting generation of reactive oxygen species and high photothermal conversion efficacy,which are essential for photothermal and chemodynamic activities.The silica nanoparticles’small size(no more than 70 nm)and high colloidal stability are prerequisites for their cell internalization.The internalization of the red-emitting silica nanoparticles within cells is visualized using fluorescence microscopy techniques.The chemodynamic activity of the silica nanoparticles is associated with their dark cytotoxicity,and the mechanisms of cell death are evaluated using an apoptotic assay.The photothermal activity of the silica nanoparticles is demonstrated by significant cell death under near-infrared(1064 nm)irradiation.